Streptococcus agalactiae, more commonly known as Group B Streptococcus, is one of the leading causes of septicemia and meningitis in newborns. The incidence of Group B disease is estimated to be 2-5 infants per 1000 live births. The early onset form of this disease occurs during the first week of life and has a mortality rate greater than 50%. When the onset occurs after day seven, the mortality rate drops to 14-23%. Newborns are at increased risk for Group B disease if they are born to women who are colonized with Group B streptococci in the vaginal or anorectal areas and who experience prolonged or difficult labor and delivery. As a strategy for prevention of Group B disease, the CDC has recommended that all pregnant women be screened for anogenital Group B colonization at 35 to 37 weeks gestation, so that intrapartum antimicrobial prophylaxis can be offered to all women identified as carriers. Screening is accomplished by obtaining vaginal and/or anorectal swabs and culturing them in recommended media such as Lim broth, incubated for 18 to 24 hours. Group B Streptococcus can also cause serious illness in adults but it far less common than in newborns.
Presumptive identification of Streptococcus agalactiae was traditionally made by physiological and biochemical methods. These include gram strain, catalase reaction, hemolytic activity on sheep blood agar plates, hippurate or L-pyrrolidonyl-β-naphthylamide (PYR) hydrolysis, CAMP and bile esculin tests. Because some Group B Streptococcus colonies are non-hemolytic on sheep blood agar, confirmative identification of Group B Streptococcus required a combination of biochemical tests and/or serological tests.
More recently, DNA probe tests have aided in the identification of Group B Streptococcus from culture. The DNA probe tests use nucleic acid hybridization for the qualitative detection of Group B Streptococcal DNA and RNA. Such tests offer a non-subjective, accurate and rapid identification method for definitively identifying Streptococcus agalactiae. 
The present invention improves upon the DNA probe tests by: increasing the sensitivity, precision and specific detection of Group B streptococci; providing for the ability of qualitative and quantitative measurements; and, increasing the speed of detection of low target copy levels due to the combination of amplification and detection in real-time.